They say the steerer is more likely to crack if you don’t have it protruding at least 10mm above the top of the stem.
So that’s what I did with the last one I cut (the only carbon one I’ve ever gotten new).
I bought a fork with the carbon steerer already cut, and to get the stem height I want, I positioned spacers so there’s 5mm of protrusion. Figure at least it’s not flush or below the stem top. I’m going to see what happens. (I know, I like living on the edge.) So far, my bike has not exploded.
